This invention relates to the field of blood-sampling devices, particularly to a disposable, pre-armed lancet device capable of constricting the finger from which the blood is to be drawn.
For purposes of medical diagnosis it is often necessary for patients to provide small specimens of blood to be analyzed. When it is required that such analyses be performed on a routine basis, as is often the case with patients suffering from diabetes or those diagnosed with the Human Immunodeficiency Virus, patients may have to obtain blood specimens without the help of a nurse or other assistant. Several disposable apparatus allowing patients to collect blood samples without the aid of others are available. Since all such devices obtain the blood by producing a small incision in the skin of the patient (most commonly the skin of one of the digits of the hand) with a sharp lancet, it is imperative that devices of this type be executed in a manner which allows them to be safely disposed after use without risking injury and possible infection to the persons who may come into contact with these devices after their disposal. Another desirable feature of instruments for collection of blood samples is the inability of the patient to anticipate the incision and to attempt to withdraw therefrom.
Even though the makers of known blood-sampling devices have attempted to address the above-mentioned concerns by providing safer and more convenient instruments, prior-art units continue to fall short in several areas. Significantly, prior-art devices require the patient (or the assistant) to either manually squeeze the blood from the incision or to employ a separate tourniquet for this purpose, thus complicating the procedure and making it more stressful for the patient. Additionally, if the act of squeezing the blood from the incision is manually performed by an assistant who massages the skin around the incision, the contact with the blood of the patient, even when made by the assistant's hands protected with surgical gloves, presents the assistant with a risk of infection. Furthermore, obtaining a blood sample from the patient's finger using a conventional lancet device often causes the patient to experience a painful sensation. This occurs when the incision in one of the digits of the patient's hand is made so that the lancet strikes too close to the bone (e.g., the distal phalanx) of the digit.